A conventional griller usually includes a lower housing and an upper housing openably covering the lower housing. When the griller is not in use, the upper housing covers the lower housing. To use the griller, the upper housing is opened and is pivoted relative to the lower housing to expose a grill plate of the lower housing for cooking food. However, the upper housing can be opened at only one maximum angle during use of the conventional griller, and cannot be adjusted in response to the need of the user, so that the conventional griller is inconvenient to use, and the market competitiveness thereof is reduced.